1. Field of the Invention
The present invention relates to hinge assemblies and, particularly, to a hinge assembly for foldable electronic devices such as portable telephones, portable computers, PDA (Portable Digital Assistant) and so on.
2. Discussion of the Related Art
At present, perhaps the most popular portable electronic device in the marketplace is the foldable cellular telephone, which generally includes a cover section and a body section. The cover section and the body section are rotatably interconnected through a hinge assembly, for switching the telephone between an in-use position and a closed position.
One kind of hinge assembly employs a compression coil spring and a cam to make the cover section open up from the body section and be held in an open position. An example of such a kind of hinge assembly is represented in FIG. 8 (Prior Art). That hinge assembly is used in a foldable mobile phone 70. The foldable mobile phone 70 includes a main housing 72 and a cover 74. The hinge assembly includes two cams 60, 62, a spring 64, and a pair of posts 76 contained in the main housing 72. The cover 74 has a channel 742 defined at an end thereof. The cam 62, the spring 64, and the cam 60 are fixed in the channel 742, in that order. The cams 60, 62 protrude out from the channel 742 and engage with the posts 76. When the cover 74 is rotated, the cams 60, 62 rotate along with the cover 74, until stopping the cover 74 in a position where it maintains an angle of 180° relative to the main housing 72.
However, the hinge assembly includes a variety of individual pieces that must be installed within the foldable mobile phone when the foldable mobile phone is assembled. This does not meet the growing trend for foldable mobile phone manufacturers to use integrated one-piece hinge assemblies that can be quickly and easily press-fitted into foldable mobile phone sub-assemblies during manufacturing. Manufacturing costs associated with non-integrated hinge assemblies are higher than those associated with one-piece hinge assemblies.
Accordingly, what is needed is a hinge assembly for devices such as mobile phones, in which the hinge assembly modularized, easy to be installed into foldable mobile phones, and low in cost.